Composite electrode tab and battery cell

Abstract

The utility model provides a kind of composite pole piece, including current collector, current collector has opposite first surface and second surface, first surface is equipped with positive active material layer, second surface is equipped with negative active material layer;The length of current collector is L1, the length of negative active material layer is L2, the length of positive active material layer is L3;The width of current collector is W1, the width of negative active material layer is W2, the width of positive active material layer is W3;L1>L2>L3, and / or, W1>W2>W3.The composite pole piece is limited to the length-width size of current collector, positive active material layer and negative active material layer, to form size gradient in the edge position of composite pole piece, reduce the step height formed between the edge of electrolyte layer and the edge of composite pole piece, to reduce the shear force received by the edge of electrolyte layer in the process of hot pressing or roll pressing, reduce or avoid the breakage of electrolyte layer.The utility model further provides a kind of battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a composite electrode and a battery cell. Background Technology

[0002] In the research and application of all-solid-state batteries, bipolar stacking structures are widely regarded as an important means to improve battery energy density and performance. A bipolar stacked all-solid-state cell generally includes multiple composite electrodes. Each composite electrode includes a current collector and positive and negative active material layers respectively disposed on opposite sides of the current collector. Multiple composite electrodes are stacked sequentially, and adjacent composite electrodes are separated by electrolyte layers (such as separators). Multiple composite electrodes and each electrolyte layer are bonded together by a hot-pressing process. Utility Model Content

[0003] To better separate adjacent composite electrodes, the electrolyte layer is generally larger in length and width than the composite electrode. Simultaneously, due to the relatively thick composite electrode, a noticeable step exists between the edge of the electrolyte layer and the edge of the composite electrode. During hot pressing or rolling, the edge of the electrolyte layer is prone to breakage due to excessive shear force (because of the noticeable step between the electrolyte layer and the composite electrode, the electrolyte layer experiences greater shear force at the step location during hot pressing or rolling, making the edge of the electrolyte layer susceptible to breakage), thus leading to internal short circuits in the cell. How to reduce or avoid electrolyte layer breakage during hot pressing or rolling without affecting the overall performance of the cell has become a pressing technical problem in the manufacturing of bipolar stacked all-solid-state cells.

[0004] The purpose of this invention is to provide a composite electrode that, by limiting the length and width of the current collector, the positive electrode active material layer, and the negative electrode active material layer, forms a size gradient at the edge of the composite electrode, reducing the step height between the edge of the electrolyte layer and the edge of the composite electrode, thereby reducing the shear force on the edge of the electrolyte layer during hot pressing or rolling, and reducing or avoiding damage to the electrolyte layer.

[0005] One embodiment of this utility model provides a composite electrode, including a current collector, the current collector having two mutually perpendicular length directions, width directions and thickness directions; along the thickness direction, the current collector has a first surface and a second surface opposite to each other; a positive electrode active material layer is provided on the first surface, and a negative electrode active material layer is provided on the second surface; Along the length direction, the length of the current collector is L1, the length of the negative electrode active material layer is L2, and the length of the positive electrode active material layer is L3; along the width direction, the width of the current collector is W1, the width of the negative electrode active material layer is W2, and the width of the positive electrode active material layer is W3; wherein, L1 > L2 > L3, and / or, W1 > W2 > W3.

[0006] In one possible implementation, the first surface includes a positive electrode active region and a positive electrode blank region, the positive electrode active material layer is disposed within the positive electrode active region, and the positive electrode blank region is disposed around the periphery of the positive electrode active material layer.

[0007] In one possible implementation, the positive electrode blank area includes a first blank area and a second blank area, wherein the first blank area is located on opposite sides of the positive electrode active area along the width direction, and the second blank area is located on opposite sides of the positive electrode active area along the length direction. Along the width direction, the size of the first blank area is K1; along the length direction, the size of the second blank area is K2; wherein, K1 > 0 mm, K2 > 0 mm.

[0008] In one feasible approach, 5mm > K1 > 0mm, 5mm > K2 > 0mm.

[0009] In one possible implementation, the second surface includes a negative electrode active region and a negative electrode blank region, the negative electrode active material layer is disposed within the negative electrode active region, and the negative electrode blank region is disposed around the periphery of the negative electrode active material layer.

[0010] In one possible implementation, the negative electrode blank area includes a third blank area and a fourth blank area, the third blank area being located on opposite sides of the negative electrode active area along the width direction, and the fourth blank area being located on opposite sides of the negative electrode active area along the length direction. Along the width direction, the size of the third blank area is K3; along the length direction, the size of the fourth blank area is K4; wherein, K3 > 0 mm, K4 > 0 mm.

[0011] In one feasible approach, 3mm > K3 > 0mm, 3mm > K4 > 0mm.

[0012] In one possible implementation, the current collector is a copper-aluminum composite foil; or, the current collector is made of stainless steel.

[0013] In one feasible manner, the thickness of the current collector is H1, where H1 is 3 μm to 10 μm; And / or, the thickness of the positive electrode active material layer is H2, where H2 is 80μm~150μm; And / or, the thickness of the negative electrode active material layer is H3, where H3 is 40μm~100μm.

[0014] Another embodiment of this utility model provides a battery cell, including a plurality of composite electrodes as described above, wherein the plurality of composite electrodes are stacked sequentially along the thickness direction, and an electrolyte layer is provided between adjacent composite electrodes.

[0015] In one possible implementation, the length of the electrolyte layer is L4 along the length direction; the width of the electrolyte layer is W4 along the width direction; wherein, L4 > L1, W4 > W1.

[0016] In one feasible embodiment, the thickness of the current collector is H1, the thickness of the positive electrode active material layer is H2, the thickness of the negative electrode active material layer is H3, and the thickness of the electrolyte layer is H4; wherein, 8> >3.

[0017] In one feasible embodiment, the thickness of the electrolyte layer is H4, where H4 is 10 μm to 45 μm.

[0018] In one possible implementation, the cell further includes a positive electrode and a negative electrode, wherein the positive electrode and the negative electrode are respectively disposed on opposite sides of the plurality of composite electrodes along the thickness direction, and the electrolyte layer is provided between the positive electrode and the outermost composite electrode and between the negative electrode and the outermost composite electrode.

[0019] In one feasible embodiment, a first current collector layer is provided on the surface of the positive electrode away from the composite electrode, and a second current collector layer is provided on the surface of the negative electrode away from the composite electrode.

[0020] The composite electrode provided by this utility model defines the length and width dimensions of the current collector, the positive electrode active material layer, and the negative electrode active material layer. Since the lengths of the positive and negative electrode active material layers are smaller than the length of the current collector, and / or the widths of the positive and negative electrode active material layers are smaller than the width of the current collector, a size gradient is formed at the edges of opposite sides of the composite electrode. This size gradient can reduce the step height formed between the edge of the electrolyte layer and the edge of the composite electrode, thereby reducing the shear force on the edge of the electrolyte layer during hot pressing or rolling, reducing or avoiding damage to the electrolyte layer, lowering the risk of internal short circuits in the cell, improving the product yield of the cell, and improving the safety performance of the battery. Attached Figure Description

[0021] Figure 1 This is a cross-sectional schematic diagram of the battery cell in an embodiment of this utility model.

[0022] Figure 2 This is a cross-sectional schematic diagram of the composite electrode in an embodiment of this utility model.

[0023] Figure 3 This is a top view of the composite electrode in an embodiment of this utility model.

[0024] Figure 4 This is a bottom view of the composite electrode in an embodiment of this utility model.

[0025] Figure 5 This is a top view of the current collector in an embodiment of this utility model.

[0026] Figure 6 This is a bottom view of the current collector in an embodiment of this utility model.

[0027] Figure 7 This is a cross-sectional schematic diagram of the current collector in an embodiment of this utility model.

[0028] Figure 8 This is a schematic diagram of the planar structure of the electrolyte layer in an embodiment of this utility model.

[0029] In the diagram: 100 - composite electrode, 1 - current collector, 10A - copper layer, 10B - aluminum layer, 11 - first surface, 111 - positive electrode active region, 112 - positive electrode blank region, 1121 - first blank region, 1122 - second blank region, 12 - second surface, 121 - negative electrode active region, 122 - negative electrode blank region, 1221 - third blank region, 1222 - fourth blank region, 2 - positive electrode active material layer, 3 - negative electrode active material layer, 4 - electrolyte layer, 5 - positive electrode, 51 - first current collector layer, 6 - negative electrode, 61 - second current collector layer. Detailed Implementation

[0030] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0031] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and claims of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0032] The directional terms such as "up," "down," "left," "right," "front," "back," "top," and "bottom" (if present) used in the specification and claims of this utility model are defined according to the position of the structures in the drawings and the relative positions of the structures, and are only for the purpose of clarity and convenience in expressing the technical solution. It should be understood that the use of directional terms should not limit the scope of protection claimed by this utility model.

[0033] like Figures 1 to 4 As shown, the composite electrode 100 provided in this embodiment of the present invention includes a current collector 1, which is a rectangular sheet structure. The current collector 1 has a length direction L, a width direction W, and a thickness direction T. Along the thickness direction T, the current collector 1 has a first surface 11 and a second surface 12 facing each other; a positive electrode active material layer 2 is provided on the first surface 11, and a negative electrode active material layer 3 is provided on the second surface 12. Both the positive electrode active material layer 2 and the negative electrode active material layer 3 are rectangular layered structures. Typically, the current collector 1 has two mutually perpendicular length directions L, width directions W, and thickness directions T.

[0034] Along the length direction L, the length of current collector 1 is L1, the length of negative electrode active material layer 3 is L2, and the length of positive electrode active material layer 2 is L3. Along the width direction W, the width of current collector 1 is W1, the width of negative electrode active material layer 3 is W2, and the width of positive electrode active material layer 2 is W3. Wherein, L1 > L2 > L3, and / or, W1 > W2 > W3.

[0035] Specifically, to better insulate adjacent composite electrode sheets 100, the length and width dimensions of the electrolyte layer 4 are generally larger than those of the composite electrode sheet 100. Compared to ordinary positive / negative electrode sheets, the composite electrode sheet 100 is relatively thicker, and the length and width dimensions of the positive active material layer 2 and the negative active material layer 3 in the existing composite electrode sheet 100 are the same as or similar to those of the current collector 1. This results in a noticeable step between the edge of the electrolyte layer 4 and the edge of the composite electrode sheet 100 after the electrolyte layer 4 is stacked with it. During hot pressing or rolling, the edge of the electrolyte layer 4 will be subjected to significant shear force due to the presence of this step. When the structural strength of the electrolyte layer 4 is insufficient to withstand this shear force, the edge of the electrolyte layer 4 will break, causing the positive active material layer 2 and the negative active material layer 3 on the adjacent composite electrode sheet 100 to come into direct contact, leading to a short circuit inside the cell and seriously affecting the safety performance of the battery.

[0036] To address the aforementioned issues, the composite electrode 100 provided in this embodiment defines the length and width dimensions of the current collector 1, the positive electrode active material layer 2, and the negative electrode active material layer 3. Since the lengths of the positive electrode active material layer 2 and the negative electrode active material layer 3 are less than the length of the current collector 1, and / or the widths of the positive electrode active material layer 2 and the negative electrode active material layer 3 are less than the width of the current collector 1, a size gradient is formed at the edges of both opposite sides of the composite electrode 100. When the electrolyte layer 4 is superimposed on the composite electrode 100, this size gradient can reduce the step height formed between the edge of the electrolyte layer 4 and the edge of the composite electrode 100, thereby reducing the shear force on the edge of the electrolyte layer 4 during hot pressing or rolling, reducing or avoiding damage to the electrolyte layer 4, lowering the risk of internal short circuits in the cell, improving the product yield of the cell, and enhancing the safety performance of the battery.

[0037] like Figure 2 , Figure 4 and Figure 6 As shown, in one embodiment, the first surface 11 includes a positive electrode active region 111 and a positive electrode blank region 112 (in... Figure 6 In the diagram, the positive electrode active region 111 and the positive electrode blank region 112 are separated by a dotted line. The positive electrode active region 111 is typically rectangular, with its length and width dimensions matching those of the positive electrode active material layer 2. The positive electrode active material layer 2 is disposed within the positive electrode active region 111. The positive electrode blank region 112 is annular, surrounding the periphery of the positive electrode active material layer 2 (i.e., surrounding the periphery of the positive electrode active region 111). No positive electrode active material layer 2 is disposed within the positive electrode blank region 112. This arrangement creates a size gradient around the edges of the first surface 11 of the composite electrode 100. When the electrolyte layer 4 is superimposed on the side of the composite electrode 100 closest to the positive electrode active material layer 2, the shear force experienced by the edges of the electrolyte layer 4 during hot pressing or rolling can be effectively reduced, thereby minimizing or preventing damage to the electrolyte layer 4. Meanwhile, since the positive electrode active material layer 2 has a certain degree of extensibility, by reserving a positive electrode blank area 112 around the four edges of the first surface 11, it is possible to avoid the positive electrode active material layer 2 from extending out of the current collector 1 and directly contacting other negative electrode active material layers 3 during the hot pressing process (the hot pressing process is a high temperature and high pressure environment), thus preventing short circuits or cross-contamination. This ensures the production yield and safety of the battery cell.

[0038] like Figure 2 , Figure 4 and Figure 6As shown, in one embodiment, the positive electrode blank area 112 includes a first blank area 1121 and a second blank area 1122. The first blank area 1121 is located on opposite sides of the positive electrode active area 111 along the width direction W (that is, the first blank area 1121 is located on opposite sides of the positive electrode active material layer 2 along the width direction W), and the second blank area 1122 is located on opposite sides of the positive electrode active area 111 along the length direction L (that is, the second blank area 1122 is located on opposite sides of the positive electrode active material layer 2 along the length direction L).

[0039] Along the width direction W, the size of the first blank area 1121 is K1, and the sizes K1 of the first blank areas 1121 on both sides are equal (of course, in other embodiments, the sizes K1 of the first blank areas 1121 on both sides may not be equal). Along the length direction L, the size of the second blank area 1122 is K2, and the sizes K2 of the second blank areas 1122 on both sides are equal (of course, in other embodiments, the sizes K2 of the second blank areas 1122 on both sides may not be equal). Wherein, K1 > 0 mm, K2 > 0 mm.

[0040] Specifically, since the positive electrode active material layer 2 extends along the width direction W and the length direction L during the hot pressing process, K1 and K2 are set to be greater than 0, so as to better avoid the short circuit or cross-contamination caused by the positive electrode active material layer 2 extending out of the current collector 1 and directly contacting other negative electrode active material layers 3 during the hot pressing process.

[0041] In one implementation, 5mm > K1 > 0mm, 5mm > K2 > 0mm; or, 4mm > K1 > 2mm, 4mm > K2 > 2mm.

[0042] like Figure 2 , Figure 3 and Figure 5 As shown, in one embodiment, the second surface 12 includes a negative electrode active region 121 and a negative electrode blank region 122 (in... Figure 5In the diagram, the negative electrode active region 121 and the negative electrode blank region 122 are separated by a dotted line. The negative electrode active region 121 is typically rectangular, with its length and width dimensions matching those of the negative electrode active material layer 3. The negative electrode active material layer 3 is disposed within the negative electrode active region 121. The negative electrode blank region 122 is annular, surrounding the outer periphery of the negative electrode active material layer 3 (i.e., surrounding the outer periphery of the negative electrode active region 121). No negative electrode active material layer 3 is disposed within the negative electrode blank region 122. This arrangement creates a size gradient around the edges of the second surface 12 of the composite electrode 100. When the electrolyte layer 4 is superimposed on the side of the composite electrode 100 closest to the negative electrode active material layer 3, the shear force experienced by the edges of the electrolyte layer 4 during hot pressing or rolling can be effectively reduced, thereby minimizing or preventing damage to the electrolyte layer 4. Meanwhile, since the negative electrode active material layer 3 has a certain degree of extensibility, by reserving a negative electrode blank area 122 around the perimeter of the second surface 12, it is possible to avoid the negative electrode active material layer 3 from extending out of the current collector 1 during the hot pressing process and directly contacting other positive electrode active material layers 2, which would cause short circuits or cross-contamination, thereby ensuring the production yield and safety of the battery cell.

[0043] like Figure 2 , Figure 3 and Figure 5 As shown, in one embodiment, the negative electrode blank area 122 includes a third blank area 1221 and a fourth blank area 1222. The third blank area 1221 is located on opposite sides of the negative electrode active area 121 along the width direction W (that is, the third blank area 1221 is located on opposite sides of the negative electrode active material layer 3 along the width direction W), and the fourth blank area 1222 is located on opposite sides of the negative electrode active area 121 along the length direction L (that is, the fourth blank area 1222 is located on opposite sides of the negative electrode active material layer 3 along the length direction L).

[0044] Along the width direction W, the size of the third blank area 1221 is K3, and the size K3 of the third blank area 1221 on both sides is equal (of course, in other embodiments, the size K3 of the third blank area 1221 on both sides may not be equal). Along the length direction L, the size of the fourth blank area 1222 is K4, and the size K4 of the fourth blank area 1222 on both sides is equal (of course, in other embodiments, the size K4 of the fourth blank area 1222 on both sides may not be equal). Wherein, K3 > 0mm, K4 > 0mm.

[0045] Specifically, since the negative electrode active material layer 3 extends along the width direction W and the length direction L during the hot pressing process, K3 and K4 are set to be greater than 0, so as to better avoid the negative electrode active material layer 3 extending out of the current collector 1 during the hot pressing process and directly contacting other positive electrode active material layers 2, which would cause short circuits or cross-contamination.

[0046] In one implementation, 3mm > K3 > 0mm, 3mm > K4 > 0mm; or, 2.5mm > K3 > 1mm, 2.5mm > K4 > 1mm.

[0047] like Figure 2 and Figure 7 As shown, in one embodiment, the current collector 1 is a copper-aluminum composite foil. The current collector 1 includes a copper layer 10A and an aluminum layer 10B stacked along the thickness direction T. A negative electrode active material layer 3 is disposed on the surface of the copper layer 10A, and a positive electrode active material layer 2 is disposed on the surface of the aluminum layer 10B. In another embodiment, the current collector 1 is made of stainless steel, that is, the current collector 1 includes a stainless steel layer (not shown), and the negative electrode active material layer 3 and the positive electrode active material layer 2 are respectively disposed on opposite sides of the stainless steel layer.

[0048] like Figure 1 As shown, in one embodiment, the thickness of the current collector 1 is H1, which is 3μm~10μm, or 5μm~15μm, or 10μm~20μm. The thickness of the positive electrode active material layer 2 is H2, which is 80μm~150μm, or 90μm~180μm, or 100μm~200μm. The thickness of the negative electrode active material layer 3 is H3, which is 40μm~100μm, or 5μm~20μm, or 10μm~30μm, or 15μm~40μm.

[0049] like Figure 1 As shown, this embodiment of the present invention also provides a battery cell, comprising a plurality of the aforementioned composite electrode sheets 100 ( Figure 1 The diagram illustrates two composite electrodes 100 (in reality, there can be more composite electrodes 100). Multiple composite electrodes 100 are stacked sequentially along the thickness direction T. An electrolyte layer 4 is provided between adjacent composite electrodes 100 to insulate and separate them. Specifically, in every two adjacent composite electrodes 100, the positive active material layer 2 on one composite electrode 100 is adjacent to the negative active material layer 3 on the other composite electrode 100. The electrolyte layer 4 is disposed between the positive active material layer 2 and the negative active material layer 3 on the two adjacent composite electrodes 100 to insulate and separate them.

[0050] Specifically, since the battery cell uses a composite electrode 100, which contains both a positive electrode active material layer 2 and a negative electrode active material layer 3, compared with traditional battery cells that use both positive and negative electrodes, it can reduce the mass ratio of the current collector 1 in the entire battery cell, thereby increasing the energy density.

[0051] like Figure 1 and Figure 8 As shown, in one embodiment, the length of the electrolyte layer 4 along the length direction L is L4; the width of the electrolyte layer 4 along the width direction W is W4. Wherein, L4 > L1, i.e., L4 > L1 > L2 > L3; W4 > W1, i.e., W4 > W1 > W2 > W3. The four edges of the electrolyte layer 4 extend beyond the four edges of the composite electrode 100, thereby allowing the electrolyte layer 4 to completely cover the composite electrode 100, thus providing better insulation.

[0052] As one implementation, 100mm > L4 > L1 > L2 > L3 > 50mm, 80mm > W4 > W1 > W2 > W3 > 30mm; or 110mm > L4 > L1 > L2 > L3 > 60mm, 90mm > W4 > W1 > W2 > W3 > 40mm; or 90mm > L4 > L1 > L2 > L3 > 40mm, 70mm > W4 > W1 > W2 > W3 > 20mm; or 80mm > L4 > L1 > L2 > L3 > 30mm, 60mm > W4 > W1 > W2 > W3 > 10mm.

[0053] In one embodiment, the electrolyte layer 4 is a solid electrolyte membrane.

[0054] In one embodiment, multiple composite electrodes 100 and each electrolyte layer 4 are bonded together by hot pressing. Since the edges of the two opposite sides of the composite electrodes 100 form a size gradient, the shear force on the edges of the electrolyte layer 4 during the hot pressing process is reduced, thereby reducing or avoiding damage to the electrolyte layer 4.

[0055] like Figure 1 As shown, in one embodiment, the thickness of the current collector 1 is H1, the thickness of the positive electrode active material layer 2 is H2, the thickness of the negative electrode active material layer 3 is H3, and the thickness of the electrolyte layer 4 is H4; wherein, 8> >3, or 6> >4, or 9> >2.

[0056] Specifically, H1 + H2 + H3 represents the total thickness of the composite electrode 100. According to actual calculations, when the total thickness of the composite electrode 100 is greater than 3 times but less than 8 times the thickness of the electrolyte layer 4 (i.e., when the total thickness of the composite electrode 100 is relatively thick), the composite electrode 100 using the above structure can achieve a more significant effect in preventing damage to the electrolyte layer 4. (However, when the total thickness of the composite electrode 100 is relatively thin, for example, less than 3 times the thickness of the electrolyte layer 4, the effect of the composite electrode 100 using the above structure in preventing damage to the electrolyte layer 4 is relatively less significant). Of course, in other embodiments, when the ratio of the total thickness of the composite electrode 100 to the thickness of the electrolyte layer 4 is not within the above range, the composite electrode 100 can also adopt the above structure.

[0057] In one embodiment, the thickness H4 of the electrolyte layer 4 is 10μm~45μm, or H4 is 5μm~30μm, or H4 is 15μm~50μm.

[0058] In one embodiment, the aforementioned battery cell can be a laminated battery cell or a wound battery cell. A laminated battery cell is formed by stacking multiple composite electrode sheets 100 and an electrolyte layer 4; a wound battery cell is formed by stacking multiple composite electrode sheets 100 and an electrolyte layer 4 and then winding them together. A wound battery cell can be a cylindrical battery cell (i.e., multiple composite electrode sheets 100 and an electrolyte layer 4 stacked and wound into a cylindrical structure) or a square battery cell (i.e., multiple composite electrode sheets 100 and an electrolyte layer 4 stacked and wound into a square structure), etc.

[0059] like Figure 1 As shown, in one embodiment, the battery cell also includes a positive electrode 5 and a negative electrode 6. Along the thickness direction T, the positive electrode 5 and the negative electrode 6 are respectively disposed on opposite sides of a plurality of composite electrodes 100. The electrolyte layer 4 is provided between the positive electrode 5 and the outermost composite electrode 100 and between the negative electrode 6 and the outermost composite electrode 100.

[0060] Specifically, the positive electrode 5 is disposed adjacent to the negative electrode active material layer 3 on the outermost composite electrode 100, and the negative electrode 6 is disposed adjacent to the positive electrode active material layer 2 on the outermost composite electrode 100. The positive electrode 5 includes a positive electrode active material layer (not shown in the figure), and the electrolyte layer 4 insulates and separates the positive electrode 5 from the negative electrode active material layer 3 on the outermost composite electrode 100; the negative electrode 6 includes a negative electrode active material layer (not shown in the figure), and the electrolyte layer 4 insulates and separates the negative electrode 6 from the positive electrode active material layer 2 on the outermost composite electrode 100.

[0061] like Figure 1As shown, in one embodiment, a first current collector layer 51 is provided on the surface of the positive electrode 5 away from the composite electrode 100, and a second current collector layer 61 is provided on the surface of the negative electrode 6 away from the composite electrode 100. The first current collector layer 51 and the second current collector layer 61 function as current collectors. The first current collector layer 51 and the second current collector layer 61 can be connected to tabs (not shown) to connect to an external circuit. Specifically, the first current collector layer 51 and the second current collector layer 61 can be current collector foils, which are high-strength conductive foils that can meet overcurrent requirements. The materials include stainless steel, copper, aluminum, and composite foils (copper-aluminum composite materials, copper-stainless steel composite materials, etc.).

[0062] This utility model embodiment also provides an all-solid-state battery, including the above-described battery cell.

[0063] The composite electrode 100 provided in this embodiment defines the length and width dimensions of the current collector 1, the positive electrode active material layer 2, and the negative electrode active material layer 3. Since the length of the positive electrode active material layer 2 and the length of the negative electrode active material layer 3 are less than the length of the current collector 1, and / or the width of the positive electrode active material layer 2 and the width of the negative electrode active material layer 3 are less than the width of the current collector 1, a size gradient is formed at the edges of opposite sides of the composite electrode 100. When the electrolyte layer 4 is superimposed on the composite electrode 100, this size gradient can reduce the step height formed between the edge of the electrolyte layer 4 and the edge of the composite electrode 100, thereby reducing the shear force on the edge of the electrolyte layer 4 during hot pressing or rolling, reducing or avoiding damage to the electrolyte layer 4, reducing the risk of internal short circuits in the cell, improving the product yield of the cell, and improving the safety performance of the battery.

[0064] Meanwhile, by setting a blank area at the edge of the current collector 1, it is possible to avoid short circuits or cross-contamination caused by the positive electrode active material layer 2 / negative electrode active material layer 3 extending out of the current collector 1 during the hot pressing process, thereby ensuring the production yield and safety of the battery cell.

[0065] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A composite electrode, characterized in that, The device includes a current collector (1), which has a length direction (L), a width direction (W) and a thickness direction (T); along the thickness direction (T), the current collector (1) has a first surface (11) and a second surface (12) opposite to each other; a positive electrode active material layer (2) is provided on the first surface (11) and a negative electrode active material layer (3) is provided on the second surface (12). Along the length direction (L), the length of the current collector (1) is L1, the length of the negative electrode active material layer (3) is L2, and the length of the positive electrode active material layer (2) is L3; along the width direction (W), the width of the current collector (1) is W1, the width of the negative electrode active material layer (3) is W2, and the width of the positive electrode active material layer (2) is W3; wherein, L1 > L2 > L3, and / or, W1 > W2 > W3.

2. The composite electrode as described in claim 1, characterized in that, The first surface (11) includes a positive electrode active region (111) and a positive electrode blank region (112). The positive electrode active material layer (2) is disposed in the positive electrode active region (111), and the positive electrode blank region (112) is disposed around the periphery of the positive electrode active material layer (2).

3. The composite electrode as described in claim 2, characterized in that, The positive electrode blank area (112) includes a first blank area (1121) and a second blank area (1122). The first blank area (1121) is located on opposite sides of the positive electrode active area (111) along the width direction (W), and the second blank area (1122) is located on opposite sides of the positive electrode active area (111) along the length direction (L). Along the width direction (W), the size of the first blank area (1121) is K1; along the length direction (L), the size of the second blank area (1122) is K2; wherein, K1 > 0 mm, K2 > 0 mm.

4. The composite electrode as described in claim 3, characterized in that, 5mm>K1>0mm, 5mm>K2>0mm.

5. The composite electrode sheet according to any one of claims 1-4, characterized in that, The second surface (12) includes a negative electrode active region (121) and a negative electrode blank region (122). The negative electrode active material layer (3) is disposed in the negative electrode active region (121), and the negative electrode blank region (122) is disposed around the periphery of the negative electrode active material layer (3).

6. The composite electrode as described in claim 5, characterized in that, The negative electrode blank area (122) includes a third blank area (1221) and a fourth blank area (1222). The third blank area (1221) is located on opposite sides of the negative electrode active area (121) along the width direction (W), and the fourth blank area (1222) is located on opposite sides of the negative electrode active area (121) along the length direction (L). Along the width direction (W), the size of the third blank area (1221) is K3; along the length direction (L), the size of the fourth blank area (1222) is K4; wherein, K3 > 0 mm, K4 > 0 mm.

7. The composite electrode as described in claim 6, characterized in that, 3mm>K3>0mm, 3mm>K4>0mm.

8. The composite electrode as described in claim 1, characterized in that, The current collector (1) is a copper-aluminum composite foil; or, the current collector (1) is made of stainless steel.

9. The composite electrode as described in claim 1, characterized in that, The thickness of the current collector (1) is H1, where H1 is 3μm~10μm; And / or, the thickness of the positive electrode active material layer (2) is H2, where H2 is 80μm~150μm; And / or, the thickness of the negative electrode active material layer (3) is H3, where H3 is 40μm~100μm.

10. A battery cell, characterized in that, It includes a plurality of composite electrodes (100) as described in any one of claims 1-9, wherein the plurality of composite electrodes (100) are stacked sequentially along the thickness direction (T), and an electrolyte layer (4) is provided between adjacent composite electrodes (100).

11. The battery cell as described in claim 10, characterized in that, Along the length direction (L), the length of the electrolyte layer (4) is L4; along the width direction (W), the width of the electrolyte layer (4) is W4; wherein, L4 > L1, W4 > W1.

12. The battery cell as described in claim 10, characterized in that, The thickness of the current collector (1) is H1, the thickness of the positive electrode active material layer (2) is H2, the thickness of the negative electrode active material layer (3) is H3, and the thickness of the electrolyte layer (4) is H4; wherein, 8> >

3.

13. The battery cell as described in claim 10, characterized in that, The thickness of the electrolyte layer (4) is H4, which is 10μm~45μm.

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