CN100405656C - Prismatic battery cell, battery with prismatic battery cell and manufacturing method thereof - Google Patents

Abstract

A prismatic battery cell comprising a positive electrode group and a negative electrode group respectively connected to a positive current collector and a negative current collector, each of said positive electrode group and said negative electrode group comprising a plurality of positive and negative electrode plates, the positive and negative electrode groups are assembled such that the positive and negative electrode plates are alternately stacked, and a separator is inserted between adjacent positive and negative electrodes, wherein the electrode plates of one electrode group are stacked together and welded on the corresponding On the current collector, the welding is substantially along the overlapping portion of the electrode groups and at least on the surface of the current collector remote from the electrode groups.

Description

Prismatic battery cell, battery with prismatic battery cell and manufacturing method thereof

field of invention

The present invention relates to prismatic battery cells, batteries with prismatic battery cells and methods for their manufacture. In particular, the present invention relates to rechargeable prismatic cells and rechargeable batteries having prismatic cells. More precisely, the present invention relates to rechargeable NiMH (Nickel Metal Hydride) rechargeable batteries having prismatic cells, although it is of course not limited thereto.

Background technique

Generally prismatic cells are the most common and commonly referred to, and are referred to as prismatic cells. A prismatic battery cell has a characteristic prismatic shape, more precisely a rectangular prismatic shape, since a battery cell is usually formed by stacking a number of generally rectangular electrode plates in parallel to form a substantially rectangular Prismatic electrode set. Each parallel electrode plate is connected to their respective current collectors, which in turn are connected to their respective terminals.

The accessories of the electrode group, the current collector and the terminal are generally packaged in a prismatic casing, so that the overall shape of the packaged battery cell is prismatic, thus it is called a "prismatic battery cell". A prismatic battery generally includes a plurality of prismatic battery cells arranged in parallel and integrally connected together such that the battery is also generally prismatic. However, it will be understood that the term "prismatic battery cell" generally refers to a battery cell having a plurality of parallel stacked electrode plates electrically connected together along their respective lateral sides, as distinguished from a cylindrical battery cell in which Each electrode group of a cylindrical battery cell comprises a plurality of generally cylindrical surface electrode plates in the shape of a helix or helically wound.

In this specification, the term "prismatic battery cell" is not meant to be defined or limited to a prismatic battery cell, but may be broadly extended to include battery cells having positive and negative electrode sets with multiple one-end connections The opposite end is not electrically connected to the parallel stacked electrode plates. The electrode plates of the positive and negative electrode groups are stacked alternately with each other and passed through the openings of the corresponding electrode groups before being connected to the corresponding current collectors. It should be understood that it is common for prismatic cells to have rectangular electrode plates, but it is neither essential nor absolutely necessary that the electrode plates be rectangular.

Batteries with prismatic cells are typically used in high current applications or applications requiring high power density. For example, rechargeable prismatic batteries such as nickel-metal hydride (NiMH) batteries have been widely used as power sources for electric vehicles (EVs) or hydrogen-powered electric vehicles (HEVs) in recent years because of their high energy density. characteristic.

Generally, electrical energy is generated by a chemical reaction between positive and negative electrode sets in a liquid electrolyte and delivered to a load first through a current collector and then through a terminal post. In many batteries, the point of contact between the electrode plates and the current collector is an important source of the battery's internal resistance. Higher internal resistance means high energy loss and introduces heat loss problems as heat will be generated at the junction between the electrode plate and the current collector. This energy loss and heating is particularly undesirable in high current applications, such as in electric or hydrogen-powered electric vehicles, as it can adversely affect efficiency and prevent premature failure in order to prevent overheating Or the battery is damaged, and the internal heat needs to be dissipated properly.

US 6,544,684 describes a prismatic cell in which current collector plates are welded to the sides of the electrode plates perpendicularly along the length of the inner surface of the current collector near the electrode plates along a plurality of selected regions.

US6,457,667 attempts to use a thermal spraying process to join electrodes and current collectors.

However, conventional battery cell structures are not entirely satisfactory, and there is still a need for improvements to prismatic battery cells and batteries incorporating the same.

Contents of the invention

According to the present invention, there is provided a prismatic battery cell comprising a positive electrode group and a negative electrode group respectively connected to a positive current collector and a negative current collector, each said positive electrode group comprising a plurality of positive electrode plates , each of the negative electrode groups includes a plurality of negative electrode plates, and the positive and negative electrode groups are assembled so that the positive and negative electrode plates are alternately stacked, and a separator is inserted between adjacent positive and negative electrodes, wherein one electrode group The electrode plates are stacked together and welded to the corresponding current collectors, the welding is generally along the stacked portion of the electrode group and at least on the surface of the current collector away from the electrode group, the current collector includes An elongated through-slot in which the overlapping portion of the electrode group is accommodated, and the electrode group is welded to the current collector substantially along the through-slot.

Preferably, the current collector is an inverted "L" shape, the through groove is on the longer side of the current collector, and the terminal of the electrode group is on the shorter side of the current collector.

Preferably, the through-slots run substantially parallel to the longer sides of the electrode plates.

Preferably, the slot is close to the center of the current collector.

Preferably, the through groove extends longitudinally along the length direction of the current collector.

Preferably, the width of the current collector is equivalent to or greater than the stack thickness of the electrode group.

Preferably, the welding portion of the current collector and the electrode plate has a substantially T-shaped cross section.

Preferably, the current collector has a thickness greater than that suitable for electron beam welding or carbon dioxide laser welding.

Preferably, the welding is arc welding, including inert gas shielded welding.

Preferably, the battery cell is a rechargeable nickel metal cell with an alkaline electrolyte.

Preferably, the overlapping portion of the electrode group is sandwiched between the current collectors.

Preferably, the battery unit is sealed inside a plastic casing, and the current collector is connected to a terminal post exposed outside the plastic casing, and the cross-sectional width of the terminal post is equivalent to the width of stacked electrode plates.

Description of drawings

Preferred embodiments of the present invention will be described in detail below by way of example with reference to the accompanying drawings, wherein:

Figure 1 shows multiple positive and negative electrode plates stacked together in parallel,

Figure 1A is a top plan view of the stacked electrode plates shown in Figure 1,

Figure 2 shows that the stacked electrode plates shown in Figure 1 are superimposed into a positive electrode group and a negative electrode group,

Figure 2A shows a top plan view of the stacked electrode set shown in Figure 2,

Figure 3A shows a partial exploded assembly view of a first preferred embodiment of an assembly comprising positive and negative electrode sets, current collectors and terminals,

Figure 3B is a partially exploded view of the fitting of Figure 3A and a prismatic battery cell housing,

Figure 4A shows a partial exploded assembly view of a second preferred embodiment of an assembly comprising positive and negative electrode sets, current collectors and terminals,

Figure 4B is a partially exploded view of the fitting of Figure 4A and a prismatic battery cell housing,

Figure 5A shows a partial exploded assembly view of a third preferred embodiment of an accessory comprising positive and negative electrode sets, current collectors and terminals,

Figure 5B is a partially exploded view of the assembly of Figure 5A and a prismatic battery cell housing,

Figure 6 shows a prismatic battery including a prismatic battery cell of the present invention.

Detailed ways

In the following descriptions of this specification, a nickel metal hydride (NiMH) battery is used as an appropriate example because nickel metal hydride rechargeable batteries are widely used and known to have high Excellent energy density characteristics and reasonable battery life. It should be understood, however, that the description, without loss of generality, applies mutatis mutandis to other types of prismatic batteries, particularly rechargeable prismatic batteries, to those skilled in the art.

Figure 1 shows a stack of positive and negative electrode plates inserted in parallel, with separators inserted between adjacent electrode plates. The electrode plates are divided into a positive electrode group 10 and a negative electrode group 20, wherein the positive electrode group includes a plurality of positive electrode plates 11 with positive leading portions 12, and the negative electrode group includes a plurality of negative electrode plates 21 with negative leading portions 22 . The positive and negative electrodes are collected together to form a prismatic unit electrode group. The electrode groups 10, 20 are arranged such that positive electrode plates 11 and negative electrode plates 21 are interlaced, and a separator 30 is inserted between each pair of positive and negative electrode plates.

Each electrode plate includes an active area 40 and a guide area 50 . The corresponding active areas of a pair of positive and negative plates are juxtaposed and react to convert chemical energy into electrical energy in the presence of an electrolyte. The active area 40 of the electrode plate of a typical prismatic battery cell is generally rectangular with the longer or longitudinal sides juxtaposed with the leading portion 50 . The guide portion 50 is generally elongated and has the same length as the longitudinal sides of the active area while being substantially rectangular. The rectangular active area of the electrode plate is generally formed from a rectangular piece of base material, so that the active area 40 and the leading portion 50 have substantially the same length. Of course, it should be understood that the effective area is generally rectangular, but this is not absolutely necessary, and the effective area may use a shape other than a rectangle without loss of generality.

In a nickel metal hydride rechargeable battery, the active area of the positive electrode plate consists of a nickel metal foam coated with nickel hydroxide. Electrode plates are typically thin to reduce material cost and weight, since the charge reactions essentially take place on the surface. The current collector is usually nickel-plated copper or steel with good thermal and electrical conductivity. For prismatic cells, the electrode plates are electron beam welded or CO2 laser welded to the current collector, which is typically a thin nickel-plated plate, because the actual fusion line is behind the welding source near the surface. Since such current collector plates have a small cross-sectional area, they are not particularly effective at conducting heat and electricity. At the position where the electrode plate is spot-welded to the current collector, the welding point usually has high resistance, so the conduction of the current collector cannot effectively dissipate unfavorable heat.

In the present invention, the lead portions 50 of the electrode plates are first stacked together. The superposition here is not limited to crimping, wrapping, gathering, welding or fastening of the respective lead parts of the electrode groups. The superimposed leading parts can be further held by soldering, welding or mechanical fastening means such as riveting. In addition, the electrode groups are typically already interleaved with adjacent electrode plates in a tightly compressed relationship before the leading portions are stacked together.

Referring to FIGS. 3A to 5B , stacked electrode groups are integrally assembled with current collectors and terminals. Fittings are inserted into a prismatic housing.

Referring to Figures 3A and 3B, a preferred embodiment of a prismatic battery cell of the present invention is shown. Referring first to FIG. 3A , the electrode plates are in a state of parallel stacked insertion structure, so that the electrode plates of the same electrode group are stacked together along the outer side and the longer free side of the guide portion. This superposition can be mechanically crimped together by, for example, the free longitudinal or longer sides of the lead parts of the electrode plates. This superposition can further be reinforced by welding or soldering of the superimposed edges of the electrode plates, or by other mechanical fastening, for example by riveting. After the electrode groups have been stacked together, the electrode groups are connected to the current collectors.

The current collector 60 of this preferred embodiment comprises two parts. The first portion 61 includes a main conductor element 61 which is generally inverted L-shaped and has a generally cylindrical stud 70 projecting from the upper surface 62 of the shorter curved end of the inverted L-shaped main conductor element. A portion of the longer side 63 of the main conductor element protrudes substantially longitudinally along the entire length of the longer side 63 of the main conductor element, so that when the longer side of the inverted L-shaped main conductor is viewed from its horizontal direction, Also has an inverted L shape.

The second part 64 comprises a generally prismatic element which cooperates with the longer extension of the main conductor element so that when the first 61 and second part 64 are soldered or welded together, the superposition of the electrode sets Partially sandwiched between the two parts, the longer side of the current collector is generally rectangular. An assembly comprising interleaved and superimposed sets of electrodes 13, 23 is mounted together with a current collector 60. After installation, the stacked electrode set is sandwiched between the two current collectors, ie the inner surfaces of the positive and negative current collectors face each other.

The installation of the assembly is described below, including stacking the electrode set and the current collector, the longer or transverse sides of the stacked electrode set being first aligned longitudinally with the longer side of the main conductor element of the current collector. The second portion 64 of the current collector 60 is then positioned by, for example, a clamp such that the longitudinally overlapping portion of the electrode group is securely clamped between the gaps formed between the first portion 61 and the second portion 64 of the current collector. The overlapping portion is then welded or brazed to the current collector substantially along its entire length, such that the two lateral sides of the electrode overlapping portion are respectively brazed to the first and second portions of the current collector.

Substantially better electrical and thermal conductivity can be obtained by making the electrical connection substantially along the entire length of the superposed part, and by making electrical contact between the two sides of the current collector close to the superposed part.

Furthermore, since the electrode plates are laminated together by welding or brazing along the front or outer surface of the current collector, welding can be better controlled and premature melting of the electrode plates is not a major problem.

Furthermore, since the superimposed portion is sandwiched between the notch formed between the first and second portions of the current collector during welding, and the welding also occurs on the front or outer surface of the current collector, the main conductor element can be sufficiently thick for Improve thermal conductivity and electrical conductivity, which not only reduces the internal resistance but also provides a better channel for heat dissipation through the current collector, then to the terminal, and to the outside world. After the fitting has been formed, the fitting is inserted into a housing 80 containing the alkaline electrode, which can then be sealed by a sealing operation. It should be noted that the housing is generally prismatic so that the sealed battery cell is also generally prismatic.

Referring to Figures 4A and 4B, a second preferred embodiment of the present invention is shown. The prismatic cell structure of the second preferred embodiment is substantially the same as that of the first preferred embodiment shown in Figures 3A and 3B. In the following description, the same reference numerals will be appropriately expanded.

Referring to Figures 4A and 4B, the current collector is a substantially inverted L-shaped main member having a through-slot extending longitudinally along the main side of the current collector, while the current connector does not have a first portion and a second portion . The longitudinal through-slot 65 is adapted to tightly accommodate the overlapping portions such that the overlapping portions of the respective electrode groups are tightly received therein along the through-slot. After the superimposed leading portions of the electrode groups have been fitted into the longitudinal channels, the superimposed leading portions of the electrode groups may be welded or soldered to the main sides of the current collector. Since the superimposed leading portion is accommodated along the through-slot, welding can be performed from the outer surface of the current collector so that better and more economical welding can be achieved.

5A and 5B show a third preferred embodiment of the present invention, the current collector of this preferred embodiment is substantially the same as that of the second preferred embodiment, but the through groove extends to the free end of the collector main body bottom, so that the electrode group The overlapping portion can be slid into position for welding along a channel extending longitudinally from the free end of the current collector.

Referring to Figure 6, there is shown a plurality of prismatic cells of any one of the preferred embodiments integrally combined in a generally parallel manner to form a prismatic cell shown in an example of the present invention.

Although the present invention has been described by the preferred embodiments above, it should be understood that the embodiments are provided as examples to help understanding of the present invention, and are not intended to limit the scope and spirit of the present invention. The scope of this invention should be determined by the general principles and spirit of the invention described above. In particular, obvious or minor changes or changes and improvements based on the present invention to those skilled in the art should be considered to belong within the scope and bounds of the present invention.

Furthermore, while the invention has been described with respect to NiMH cells, it should be understood that the invention, with or without modification, can be applied to other prismatic cells without loss of generality.

Claims (13)

1. prismatic battery cell, comprise a positive electrode group and a negative electrode group of being connected on a positive current-collector and the negative current-collector, each described positive electrode group comprises a plurality of positive electrode plates, each described negative electrode group comprises a plurality of negative electrode plates, described positive and negative electrode assembling is made into positive-negative electrode plate is alternately piled up, and between adjacent positive and negative electrode, insert dividing plate, wherein, the battery lead plate of an electrode group is superimposed, and be welded on the corresponding current-collector, this welding is substantially along the overlapping portion of electrode group, and be positioned at least on the surface away from the described current-collector of described electrode group, it is characterized in that described current-collector comprises the groove of a strip, wherein accommodate the overlapping portion of described electrode group, described electrode group is welded on the described current-collector along described groove substantially.

2. battery unit according to claim 1 is characterized in that, described current-collector is inverted "L" shaped, and described groove is on the long one side of described current-collector, and the binding post of electrode group is on the short one side of current-collector.

3. battery unit according to claim 1 is characterized in that, described groove is parallel to the long side of described battery lead plate substantially and stretches.

4. battery unit according to claim 1 is characterized in that, described groove is near the center of described current-collector.

5. battery unit according to claim 1 is characterized in that, described groove is along the length direction extending longitudinally of described current-collector.

6. battery unit according to claim 1 is characterized in that, the width of described current-collector is equivalent to or greater than the stack thickness of described electrode group.

7. battery unit according to claim 1 is characterized in that, this welding portion of described current-collector and described battery lead plate has the cross section that is substantially T shape.

8. battery unit according to claim 1 is characterized in that, the thickness of described current-collector is greater than the thickness that is suitable for the welding of electron beam welding or carbon dioxide laser.

9. battery unit according to claim 1 is characterized in that, describedly is welded as arc-welding, comprises inert gas-shielded arc welding.

10. battery unit according to claim 1 is characterized in that, described battery unit is the chargeable nickel metal battery unit with alkaline electrolyte.

11. battery unit according to claim 1 is characterized in that, the overlapping portion of described electrode group is clipped between the described current-collector.

12. battery unit according to claim 1 is characterized in that, described cell seal is a plastic casing inside, and described current-collector is connected on the binding post that is exposed at described plastic casing outside.

13. a prismatic battery comprises each prismatic battery cell of aforementioned claim.

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