battery-dat/battery-tools-dat/battery-tools-dat.md
... ...
@@ -14,7 +14,7 @@
14 14
15 15
- [[tools-dat]] - [[soldering-tools-spot-welding-dat]]
16 16
17
-- Nickel Strip / copper strip == 铝片和铜片，电池点焊用的，铝片适合铝壳电池，铜片适合铁壳电池
17
+- Nickel Strip / copper strip == 铝片和铜片，电池点焊用的，铝片适合铝壳电池，铜片适合铁壳电池 - [[soldering-materials-dat]]
18 18
19 19
- [[internal-resistance-meter-dat]]
20 20
tools-dat/soldering-tools-dat/soldering-materials-dat/soldering-materials-dat.md
... ...
@@ -0,0 +1,57 @@
1
+
2
+
3
+# soldering-materials-dat
4
+
5
+
6
+Nickel, Copper, and Sandwich (For 18650/21700)
7
+
8
+| Material | Best Use Case | Pros | Cons |
9
+| :-------------- | :--------------------------------- | :--------------------------------------------------------------------------- | :--------------------------------------------------------------------- |
10
+| **Pure Nickel** | Standard DIY packs (5A-15A) | Easiest to spot weld; corrosion resistant. | Higher resistance than copper; heats up at high current. |
11
+| **Pure Copper** | High-performance (30A+) | Lowest resistance; minimal heat generation. | Extremely difficult to spot weld (requires laser/ultrasonic). |
12
+| **Sandwich** | High-current DIY (Nickel + Copper) | Better conductivity than pure nickel; weldable with high-power spot welders. | Hard to tune welding parameters; risk of "cold" welds or blow-through. |
13
+
14
+
15
+
16
+---
17
+
18
+### 2. Al-Ni (Aluminum-Nickel) Composite Strips
19
+
20
+**Primary Purpose:** Transitioning between dissimilar metals.
21
+
22
+* **When to use:** Specifically for **Pouch Cells** or **Prismatic Cells** where the positive terminal (tab) is made of **Aluminum**.
23
+* **Why:** Aluminum and Nickel do not bond well through standard spot welding.
24
+* **How it works:** The strip is bi-metallic (half Al, half Ni).
25
+ * **Al side** is welded to the battery's Aluminum tab.
26
+ * **Ni side** provides a weldable surface for standard nickel busbars or wires.
27
+* **Summary:** It is a "bridge" material, not for 18650s (which use steel/nickel caps), but for batteries with raw aluminum electrodes.
28
+
29
+
30
+
31
+
32
+
33
+
34
+## 18650 Interconnect Materials: Why vs. Why Not
35
+
36
+| Material | Conductivity | Weldability | Best Used For... |
37
+| :-------------- | :---------------- | :------------ | :----------------------------------------------------------- |
38
+| **Pure Nickel** | Good (~25% of Cu) | **Excellent** | Standard DIY packs, Robotics (Rover V2), Electric bikes. |
39
+| **Pure Copper** | **Best (100%)** | **Very Poor** | Ultra-high performance racing drones or EV modules. |
40
+| **Sandwich** | High | **Difficult** | High-current DIY builds (Copper strip under a Nickel strip). |
41
+
42
+---
43
+
44
+### Why we choose Pure Nickel for 18650s:
45
+1. **High Resistance (Ideal for Welding):** Spot welding relies on electrical resistance to generate heat. Nickel resists current just enough to melt instantly at the contact point, creating a strong bond.
46
+2. **Thermal Control:** Copper is a "heat sink"—it pulls heat away so fast that the weld point never gets hot enough to melt, but the battery cell underneath gets dangerously hot.
47
+3. **Corrosion Resistance:** Nickel does not rust or oxidize easily. Copper turns green (oxidizes) over time, which increases resistance and creates "hot spots."
48
+4. **Tool Compatibility:** Most hobbyist spot welders (Sunkko, Malectrics, Kweld) are designed specifically for the physics of nickel.
49
+
50
+
51
+
52
+## ref
53
+
54
+- [[soldering-tools-dat]]
55
+
56
+
57
+
tools-dat/soldering-tools-dat/soldering-tools-spot-welding-dat/soldering-tools-spot-welding-dat.md
... ...
@@ -9,6 +9,10 @@
9 9
10 10
- [[capacitor-super-dat]] - [[capacitor-dat]]
11 11
12
+
13
+- 可焊0.25mm
14
+
15
+
12 16
![](2025-06-13-13-43-52.png)
13 17
14 18
specifically for [[battery-dat]]